13.1 Error Handling: errcont, retry

There is also a difference in the handling of errors. In the former case, the computation can continue since you have the opportunity to correct the mistake. In batch mode, the error may lead to consequent erroneous (and possibly time consuming) computations. So in the default case, no further evaluation occurs, although the remainder of the input is checked for syntax errors. A message "Continuing with parsing only" informs you that this is happening. On the other hand, the switch errcont, if on, will cause the system to continue evaluating expressions after such errors occur.

When a syntactical error occurs, the place where the system detected the error is marked with three dollar signs ($$$). In interactive mode, you can then use ed to correct the error, or retype the command. When a non-syntactical error occurs in interactive mode, the command being evaluated at the time the last error occurred is saved, and may later be reevaluated by the command retry.

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